Current touch screens found in display devices, such as display devices for portable electronic devices like smartphones and tablets, have limitations on the functions that they can perform. For example, current touch screens react to finger touches only, and while capable of displaying images, are not able to sense high resolution objects, such as fingerprints or palm prints, and are not able to read documents or other image-like inputs. As a result, current touch screens are not able to provide adequate biometric support functions or scanning functions. Also, the current touch screens found in display devices can seldom be read in both bright and dim areas.
Known screens for devices such as laptops and mobile devices display information using liquid crystal display (LCD) modulation of ambient light or a backlight, or by light emitting diode (LED) emission at desired areas (e.g., pixels). To sense touch, known screens typically include a sensing layer, such as a capacitive or resistive touch sensor. Other less common techniques for sensing touch include surface acoustic waves or arrays of photo-beams. Known techniques for sensing touch add complexity to a device in terms of manufacture as well as in terms of registration (e.g., corresponding a touch location with a display location).
In addition, known screens using touch sensors typically do not have enough resolution to sense biometric parameters. For instance, a multi-touch screen cannot determine the shape of the user's hand when applied to the screen (e.g., finger lengths and knuckle widths). In general, current touch sensors cannot perform imaging, such as would be needed to extract a fingerprint for biometric authentication. Such biometrics provide an added layer of security and non-repudiability that can be convenient, and a desirable property for a device.
Accordingly, there is a need for a display device and method of using same that includes a display screen that is capable of functioning as a touch screen and providing biometric support and scanning functions.